The P0174 trouble code detected by your Ford V8 engine control unit--or engine computer--is warning you about an excess of oxygen in the exhaust system. During normal operation, the engine management system on your vehicle sets the right air-fuel mixture for better engine performance with a minimum of emissions. In most cases, the mass air flow sensor (MAF) and vacuum system trigger this code due to contamination or failure. This guide will give you the most common steps to fix Code P0174.
Park your car in a safe place, open the hood and locate the MAF sensor on the air duct of the air intake assembly.
Disconnect the black, negative battery cable and unplug the sensor electrical connector being careful not to break the plastic locking tabs.
Remove the sensor from the air duct using a Phillips screwdriver or ratchet and socket.
Clean the sensor using electronic parts cleaner according to the manufacturer's specifications. Install the sensor and connect the black, negative battery cable.
Test the sensor using a multimeter and make sure it is in good operating condition. If necessary, consult your vehicle service manual for the best testing procedure and electrical values for the particular sensor used on your vehicle. If your voltage readings are out of range of the manufacturer's specifications, replace the sensor.
Check vacuum hoses, hose connectors and fittings especially along the air intake assembly. Check for loose fittings, torn, obstructed or otherwise damaged hoses. Disconnect vacuum hoses and make sure they are free of any obstruction. Replace vacuum hoses if necessary.
Check the fuel system. Replace the fuel filter if you have not done so in the previous 12 months. Make sure the system has the correct pressure. An obstructed fuel filter or damaged fuel pressure regulator may cause a drop in fuel supply to the intake system.
